1. Field of the Invention
The present invention relates to a photographic printing apparatus which prints images which are recorded on a film.
2. Description of the Related Art
In order to effect correction of the printing conditions of an image recorded on a film and the like, a photographic printing apparatus is provided with a simulator function for displaying the image on a display. In this type of a photographic printing apparatus, the image recorded on the film is projected so that the image is displayed on the screen of the display before being printed onto photographic printing paper.
Conventionally, a two light source method has been used in which a light source for printing and a light source for projecting the image recorded on the film are provided separately. Light which is irradiated from the light source for projecting and which passes through the image enters a projecting element. Further, an inclined photometric method has been used in which photometry and projecting are effected at an angle with respect to the image surface of the image. However, in this method, it is necessary to provide the second light source. Therefore, the cost is high, and the additional light source occupies space. Further, the direction in which the film is conveyed cannot easily be turned 90.degree.. The degrees of freedom in arranging the conventional photosensitive printing apparatus are thereby reduced. Moreover, using an inclined photometric method results in drawbacks such as warping of the image displayed on the display, and the like.
A method has been considered in which light irradiated from a light source and passed through an image is reflected by a half mirror which is disposed so as to be fixed on the printing optical path. Another method has been known in which light irradiated from a light source and passed through an image is reflected by a total reflection mirror which is moved so as to be disposed on the optical path for printing during photometry and is withdrawn from the printing optical path during printing when one image is printed. The light reflected by the half mirror or the total reflection mirror enters a projecting element to be photometrically measured. However, when the half mirror is used, an optical disturbance may be created. Further, when the total reflection mirror is used, the time required to move the total reflection mirror is added to the entire processing time, and printing processing cannot be effected at high speed. It is hazardous to move the total reflection mirror rapidly in order to shorten the processing time.
The applicant solved the above-described drawback in Japanese Patent Application Laid-Open No. 2-278248 which discloses a photographic printing apparatus in which printing processing time is shortened. In this apparatus, when a film of 135 size or less is printed, a half prism is attached to a zoom lens inserted into the printing optical path so as to guide a portion of the light passing through the photographic film to a projecting element. When a film which is larger than size 135 is printed, a total reflection mirror is inserted into the printing optical path and the light is reflected to a projecting element. A total reflection mirror is used because a large half prism is expensive.
In this way, when films of 135 size or less which have many images to be processed are successively printed, a portion of the light is reflected to the projecting element by the half prism. Therefore, there is no member moved into the optical path, and printing processing can be effected quickly and economically.
When a film larger than 135 size, e.g., a brownie size film, is printed, the total reflection mirror must be inserted into and withdrawn from the printing optical path each time a frame is printed. Since there are few images to be processed in films which are larger than 135 size, the time involved in moving the total reflection mirror does not greatly effect the total processing time. Accordingly, even though the total reflection mirror is moved comparatively slowly in order to maintain stability, there is no great increase in the processing time.
However, compared with a method in which only a half-mirror or only a total reflection mirror are used in the photographic printing apparatus, it is necessary to adjust not only the optical position of the mirror but also that of the half prism. Therefore, the work involved in adjusting the optical system of the photographic printing apparatus is complicated. Further, there is a drawback in that the cost of the photographic printing apparatus is high because the half prism is expensive.